Distal protection device with local drug delivery to maintain patency

ABSTRACT

The present invention provides for a drug delivery mechanism for use with a protection device. The protection device has an expandable filter. The drug delivery mechanism automatically delivers a drug to the filter without requiring the intervention of the operator of the protection device. The drug delivered to the filter facilitates continued filter patency during the medical procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a regular application filed under 35 U.S.C. § 111(a)claiming priority, under 35 U.S.C. § 119(e) (1), of provisionalapplication Serial No. 60/337,664 and application Ser. No. 60/337,936,both previously filed Nov. 7, 2001 under 35 U.S.C. § 111(b).

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to medical devices forfiltering or removing matter from within a vascular system and thedelivery of drugs to maintain continued filter patency. Morespecifically, the present invention relates to a protection devicehaving a drug delivery system for facilitating patency of the protectiondevice. This device also relates to any other interventionalapplications where patency must be maintained. This includes suchapparatus as stents, grafts, vessel liners, and guide catheters

[0004] 2. Description of Related Art

[0005] A protection device, generally, is an expandable filter attachedto a hostwire. Protection devices are often employed in interventionalcardiology/radiology applications to allow the flow of fluid, such asblood, while preventing the passage of particulate matter, such asemboli. Protection devices are often referred to as distal protectiondevices where the term “distal” refers to the positioning of theprotection device distal to a lesion or treatment site relative to flowin the vessel. The filter portion of existing protection devices mayinclude such items as braided meshes, woven fabrics, perforated films, aplurality of crossing wires, electrospun polymers and any otherconfiguration suitable for filtering.

[0006] The performance of the protection device requires that the filtermaintain patency. Patency is defined as the ability of the filter toallow the passage of fluid. Patency may refer to a filter at a specificpoint in time and/or the amount of time that a filter is able tomaintain non-occlusiveness. When used in a vascular system, the patencyof the filter typically decreases over a period of time. As the poresize of the filter decreases, the patency will decrease relative to thatfor a greater pore size. For example, in some filters when the maximumpore size is 100 um there may be pores ranging in size from 20 um orless. Such a fine pore size may cause a filter to become occluded bydebris. Pores below a crucial pore size may also become occluded byformation of an impermeable fibrous sheet that may close off flowthrough the pore.

[0007] The current art utilizes three different mechanisms forfacilitating patency. A mechanism facilitates patency where themechanism allows greater flow-through, when compared to the performanceof a similar filter without the mechanism.

[0008] The first mechanism used in the current art involves thepre-application of coatings on the filter used to prevent bloodclotting. Such coatings include anti-coagulants, anti-thrombogenics,anti-platelets or other such drugs. One typical drug of this nature isheparin. Even with such coatings the patency of the filter is limitedbecause the drug coating is eventually overcome by clotting forces inthe blood. Such a mechanism results in the patency beginning to decreaseas soon as the coating contacts the clotting agents of the blood, and itis only a matter of time before filter patency is reduced or eliminatedby the clotting agents.

[0009] Two other mechanisms in the prior art used to provide forincreased filter patency include dipping the filter in an anti-coagulantsuch as heparin solution, or a systemic use of drugs such as a IIb/IIIainhibitor. Even with dipping in heparin, the patency of the filter willdeteriorate over a relatively short period of time. Problems withsystemic use of drugs may manifest themselves as excessive patientbleeding.

SUMMARY OF THE INVENTION

[0010] The present invention is a protection device with a local drugdelivery system. The drug delivery system delivers a drug for increasingfilter patency. The protection device includes a hostwire to which anexpandable filter is mounted, and an embodiment of an improved drugdelivery mechanism for facilitating filter patency is described herein.

[0011] Local drug infusion helps to maintain patency of the filter whileblood is flowing through the filter. Local drug infusion provides theeffects of the drug in a local concentration where needed, to maintainfilter patency while minimizing the possible side effects (i.e.excessive bleeding) that the drug could cause if used systemically.Generally, the drug is delivered upstream of the filter, proximate thefilter, and allowed to flow distally, through the filter with the blood.

[0012] A first embodiment of the present invention is a drug deliverymechanism comprising a micro-electro mechanical system (MEMS) on or in aguide coil. The guide coil is wound about the hostwire either proximalor distal to the filter or both. The MEMS is positioned near a first endof the guide coil. The MEMS is able to automatically advance toward thesecond end of the guide coil by ratcheting a predetermined distancealong the guide coil. The guide coil may be a shape memory tubular bodycontaining a drug. As the MEMS ratchets along a length of the coil, thedrug is released from the guide coil. The drug is then delivered to thefilter so as to induce continued filter patency.

[0013] Another embodiment of the present invention utilizes a MEMS on aguide wherein packets or beads containing a drug are on the surface ofthe guide. As the MEMS ratchets along the surface of the guide, thepackets or beads are pierced, thus causing the release of the drug.

[0014] Still another embodiment of the present invention utilizes a drugdelivery system comprising drug eluting beads. The beads may be locatedon the hostwire, within the filter, electrospun to the filter, distal tothe filter and/or proximal to the filter or a combination thereof. Thebeads are solid forms of variable shape that allow a drug to be harboredon or within the bead such as in a crevice, pore, surface, underneath orwithin a coating, dissolved into the bulk of the bead, or any other suchmeans of harboring a drug. The beads may release the drug on deploymentof the protection device or under predetermined environmental orbiological conditions that induce the release of the drug. The drug maybe released such as by piercing of the beads, dissolving of a coating onthe beads, or any other suitable method of activating the delivery of adrug. The beads may be activated by piercing where the beads arereleased from the hostwire and allowed to impact the filter causing thebeads to be pierced. The drug would then be released on the filter so asto automatically induce increased filter patency without physician oroperator intervention. The beads may also have a coating or a shape orform that regulates or controls the release of the drug and deliver thedrug to the filter such as by a stimuli sensitive polymers or other suchcoatings.

[0015] Another embodiment of the present invention comprises a hydrogelor a gel conjugate that is used to coat the filter and/or hostwire. Thegel acts as a drug delivery system wherein the gel may be activated byenvironmental or biological agents or variables such as ph, temperature,pressure differential, precursors to fibrin formation, and the like.

[0016] Another embodiment of the present invention has a drug deliverymechanism received within a lumen of a tubular member for providinglocal drug infusion such as through a plurality of weep holes at adistal portion of the tubular member. An expandable bladder is locatedwithin the hollow portion. The bladder expands upon the occurrence of apredetermined environmental condition such as temperature or pressuredifferential or inflation with a syringe. The drug occupies the lumenwith the tubular member. As the bladder expands the drug is releasedthrough weep holes through a wall defining the tubular member anddelivered to the filter.

[0017] The present invention thereby provides for a local drug deliverymechanism for providing a drug to a protection device such as a filterfor inducing and facilitating filter patency frequently withoutrequiring interaction from a physician or operator.

DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a side view of a protection device with a micro-electromechanical system for providing drug delivery;

[0019]FIG. 2 is a side view of a protection device with a plurality ofelectro mechanical systems for providing drug delivery;

[0020]FIG. 3 is a magnified side view of an electro mechanical systemand guide member;

[0021]FIG. 4 is a side view of a protection device with drug elutingbeads on the hostwire;

[0022]FIG. 5 is a side view of a protection device with drug elutingbeads spun about the expandable filter;

[0023]FIG. 6 is a side view of a protection device with drug elutingbeads positioned within the expandable filter;

[0024]FIG. 7 is a side view of a protection device having a drugcoating;

[0025]FIG. 8 is side view of a protection device with a hollowed portionwith an expandable bladder for drug delivery;

[0026]FIG. 9 is a side view of a protection device with a fluted hollowportion;

[0027]FIG. 10 is a side view of a protection device having adjacentlumens for drug delivery; and

[0028]FIG. 11 is a side view of a protection device having coaxiallumens for drug delivery.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029]FIG. 1 illustrates a first embodiment of a protection device 10with a drug delivery mechanism 15 for automatically delivering a drugwithout operator or physician input. The protection device 10 is shownhaving a filter 12 that can be expanded or collapsed about a hostwire14. The drug delivery mechanism 15 includes a coiled tube 32 helicallywound with respect to an axis of elongation defined by the hostwire 14.Also shown, is a proximal marker band 16 and a distal marker band 17.

[0030]FIG. 1 depicts only the distal portion 13 of the hostwire 14,wherein the term ‘distal’ refers to the downstream end of the hostwire14 with respect to flow in the body vessel, and the term ‘proximal’refers to the upstream end with respect to flow in the vessel.

[0031] Use of the protection device 10 includes advancing the protectiondevice 10 within a lumen and expanding the protection device to engage awall of the lumen. Once expanded, the filter 12 is able to filter fluidflowing through the lumen so as to prevent particulate matter frompassing distal to the filter 12. Most commonly, the protection device 10is used to filter particulate matter entrained in blood such as in ablood vessel of a patient's vascular system.

[0032] The drug delivery mechanism 15 is configured to deliver the drugto the device 10 such as by leaching or metered methods that occurautomatically without physician input once the protection device 10and/or filter 12 is deployed. When used in the vascular system, thefilter 12 may become at least partially occluded as a result of bloodcoagulation and/or clotting. Upon delivery of the drug to the protectiondevice 10 by the drug delivery mechanism 15, the drug is able to induceor facilitate continued filter patency.

[0033] The drug delivery system embodied in FIG. 1 is a micro-electromechanical device (MEMS) 30. The MEMS 30 is positioned proximal thefilter 12. The MEMS 30 is positioned on a guide 32 such as a coiled tube32. The guide 32 is positioned about an axis of elongation defined bythe hostwire 14. The MEMS 30 is able to ratchet along the length of theguide 32. The drug is dispensed and delivered by the MEMS 30 as the MEMS30 advances at predetermined intervals along the length of the guide 32.It is contemplated that the MEMS 30 begin at or near a first end of acorresponding guide 32 and ratchet in the direction of a second end ofthe corresponding guide 32. Alternatively, the guide could be straightwire or tube running parallel to the hostwire, or could be the hostwireitself.

[0034]FIG. 2 illustrates a plurality of MEMS 30 utilized as a drugdelivery mechanism 15. A first MEMS 30 may be positioned proximal to thefilter 12 and a second MEMS 30 may be positioned distal to the filter12. As illustrated, each MEMS 30 is positioned on a guide 32 such as acoiled tube 32. Each MEMS 30 is able to ratchet along the length of theguide 32. The drug is dispensed and delivered by each MEMS 30 atpredetermined intervals.

[0035] It is further contemplated that the drug delivery mechanism 15may, instead, comprise only a single MEMS 30 and guide 32 such that theguide 32 and MEMS 30 are positioned distal to the filter 12.

[0036]FIG. 3 illustrates a magnified view of a MEMS and coil drugdelivery system 15. The function of the drug delivery system 15 is todeliver a drug to the filter to facilitate patency of the filter 12. Thedrug is released by the movement of the MEMS 30 along the length of theguide 32. For example, the drug may be located within a lumen 52 orother such compartment within the guide 32. As the MEMS 30 ratchetsalong the length of the guide 32 from a first end 54 toward a second end56, the drug is forced or induced out the second end 56 of the guide 32and released into the blood stream or onto the protection device 10and/or filter 12. It is beneficial, but not necessary, that the secondend 56 of the guide 32 be the end nearest the filter 12 for greatestbenefit toward facilitating filter patency.

[0037] The guide 32 may be a coil made of a shape memory material suchas an alloy or from a drug-loaded shape-memory polymer material. TheMEMS 30 may be positioned over the guide 32 or marker band 16 orhostwire 14, and may have a shape such as a donut shape that slidesalong the delivery guide 32.

[0038] Alternatively, the coiled tube 32 could be made of a shape memorypolymer and drug loaded such that the drug is released upon a reactionto pressure, temperature, flow characteristics such that the drug may bereleased from a storage portion 52 within the tube without the use ofthe MEMS.

[0039] Another method for drug delivery using the MEMS 30 and guide 32utilizes drug packets and/or beads 50. For example, packets of the drugmay be located on the surface 58 of the guide 32. As the MEMS 30advances from the first end 54 toward the second end 56 of the guide 32,over the packets 50, the packets 50 are pierced or broken causing thepackets to dispense or release the drug. For this drug delivery system15 it is beneficial, but not necessary, that the first end 54 of theguide 32 be nearest the filter 12 with respect to the second end 56. Thereason being that the drug is released after the MEMS 30 ratchets overthe packet 50.

[0040] The drug delivery system comprising the MEMS 30 and guide 32 maybe positioned proximate or adjacent to the filter 12. The drug may bereleased or delivered directly onto the filter 12, marker band 16,and/or hostwire 14. Alternatively, the drug may be released or deliveredinto the bloodstream of a patient and allowed or directed to flow to thefilter 12.

[0041] The initiation of the drug delivery system may occur upondeployment of the protection device 10. Prior to deployment of theprotection device 10, the filter 12 is collapsed toward the hostwire 14.In this collapsed configuration, the coil 32 may be deformed ormaintained in a predetermined position on the guide 32 so as to preventthe MEMS 30 from advancing. Once the filter 12 is expanded, the coil 32can resume its preformed state that allows the MEMS 30 to becomeself-activated and begin dispensing the drugs for inducing continuedpatency of the filter 12. Self-activation of the drug delivery mechanismmay occur by any such method wherein deployment of the filter 12functions to remove any restriction on the MEMS 30 from advancing alongthe guide 32.

[0042] The drug released by the drug delivery mechanism 15 may be anysuch drug that prevents clotting of the blood or otherwise induces orfacilitates continued filter patency, such as heparin, Integrilin,Aggrastat, or fibrinolytic drugs Such drugs may react with bloodplatelets, blood clotting agents, precursors to the formation of bloodclots, and any other agents having a role in the formation of bloodclots, coagulation, and reversal of same.

[0043] The drug may be dispensed at predetermined intervals by the MEMS30 where the MEMS 30 ratchets a predetermined length along the guide 32at predetermined time intervals resulting in the dispensing of the drugat periodic intervals.

[0044] A hydrogel, or other leachable coating laden with a drug can bedelivered and/or applied to the filter 12, marker bands 16, and/or thehostwire 14 proximal to the filter 12. This can also be applied to theinside or outside diameter of a guide catheter used to deliver theprotection device 10 to a location within a patient's vascular system,for example. Some drug methods common to those of ordinary skill in theart include pe-dipping with albumin, heparin or calcium channelblockers. Hydrogels in combination with drugs can be used alone or incombination with MEMS. The methods for making a MEMS 30 as describedherein are common to those of ordinary skill in the art as is the use ofvarious drugs that may be delivered by the MEMS 30 to facilitate patencyof the filter 12 and protection device 10.

[0045] The MEMS 30 may have any shape, such as a short-tubular or donutshape in the preferred embodiment. Any shape may be used that allows theMEMS 30 to advance along the guide 32 and release drugs for continuedpatency of the filter 12. The guide 32 may likewise have any shape thatallows the MEMS 30 to ratchet along the guide 32 so as to provide a drugdelivery mechanism 15 to the protection device 10.

[0046] FIGS. 4-6 illustrate yet another embodiment of the presentinvention. As in FIGS. 1-3, a protection device 10 is shown having anexpandable filter 12 attached proximate the distal end of a hostwire 14.The filter 12 has proximal and distal marker bands 16, 17 on respectivesides. The drug delivery mechanism 15 in this embodiment is a polymercontaining structure illustrated in the figures as drug eluting beads50. It will be understood, however, that structures shaped other than as“beads” would be acceptable. The beads 50 which are shown may bepositioned on the hostwire 14 as shown in FIG. 4. Fibers attached to thefilter 12 as in FIG. 5, can have the drug mixed with a polymer. FIG. 6illustrates a multiplicity of beads received within a capture space offilter 12. These examples are illustrative, however, and not limiting asto the use of drug eluting structures for delivery of a drug to inducecontinued patency within a filter 12. Each embodiment illustrated isdiscussed separately below.

[0047]FIG. 4 shows an alternative drug delivery apparatus comprising ahostwire 14 extending through a filter 12, and drug eluting beads 50mounted on the hostwire 14. The drug eluting beads 50 may be piercedduring deployment resulting in release of the drug. Alternatively, thedrug could be permitted to leach out of the beads or other polymercontaining structure. Piercing of the drug eluting beads 50, whenpiercing is utilized, may occur upon deployment of the filter 12 to theexpanded configuration. For example, the drug eluting beads 50 may beaffixed to the hostwire 14 such that when the filter 12 is deployed, thebeads 50 will be pierced by the wires of the filter 12. The beads 50 mayalternatively be pierced where, upon deployment, the beads 50 arereleased from the hostwire 14 and allowed to flow, project, or travelinto the filter 12. As the beads 50 impact strands forming the filter12, the beads 50 may become pierced by the filter strands, thus causingthe release of the drug for continued filter 12 patency.

[0048]FIG. 5 illustrates the drug eluting beads 50 attached to strandsof the filter 12. The beads 50 may be formed by spinning polymer strandsonto the filter 12 and then post processing the strands to form beads.Such beads can be formed on the filter or into the filter. Such beads 50may be a polymer material intermixed or absorbed or filled with the drugsuch that instead of creating a polymer strand during the formingprocess, they create a polymer bead containing the drug for facilitatingpatency of the filter 12. Alternatively, the fibers can have the drugmixed immediately with the polymer.

[0049]FIG. 6 illustrates drug eluting beads 50 positioned within acapture space of the filter 12. The drug eluting beads 50 would have adiameter greater than the filter pores so that the beads 50 aremaintained within the filter 12.

[0050] The beads 50 are self-activating such that the drug may bedelivered during deployment of the protection device 10 or filter 12.The initiation of the drug release may be activated either by piercingof the beads 50 or by interaction of the beads 50 and/or drug with theenvironment in which the protection device 10 is deployed, such asagents in blood that may initiate activation of the drug or the releaseof the drug, such as by the drug leaching out of the beads 50.

[0051] The drug eluting beads 50 may be composed of a polymer material.The drug may be contained within the beads 50 or coated about thesurface of the beads 50 or within pores within the beads, dissolved inthe beads, or a combination thereof. The drug eluting beads 50 may havea coating thereon, such that the drug is eluted only after the coatingis pierced or activated by leaching out of the beads 50. Thus, aself-activating coating may be used to prevent release of the drug untilintended activation of the drug delivery mechanism such as by anactivating agent found in blood. The coating may further be dissolved byan activating agent in the blood such as platelets or other precursorsto coagulation. The drug delivery method using beads 50 may includeimmediate drug delivery once the device is deployed, or timed release ofthe drug continuing over a 30 to 60 minute, or longer, time period, or avariable release time depending on the material and configuration.

[0052] The beads 50 may be porous or non-porous, and take on many shapessuch as that of a rod, sphere, oval, and the like. Further, the beads 50may be located on the coil or guide 32 such as for use with an MEMS 30,as in FIG. 1. The drug may be a smart-release or passive release. Theabove examples of drug eluting beads 50 are illustrative and notlimiting as to the use of beads 50 as the drug delivery mechanism toinduce continued patency of the filter 12.

[0053]FIG. 7 illustrates yet another embodiment of the presentinvention. A drug coating 110 is placed on protection device 10proximate the filter 12, illustrated by the areas identified byreference numeral 110 in FIG. 7. The coating 110 may be positioned onthe hostwire 14, marker bands 16, the filter itself, in combination oralternatively on surface of the protection device 10. The coating 110may be a hydrogel or other such coating. The hydrogel coating may actsimilar to the beads 50, previously discussed, wherein the hydrogelcontains a drug or is coated with a drug such that the hydrogel acts asa drug delivery mechanism. The drug may also be smart released orpassively released depending on the characteristics of the drug,hydrogel, coating, or combination thereof.

[0054] Drugs can also be incorporated into a gel conjugate locatedproximal to the filter 12 such as in conjunction with the otherembodiments of the present invention. The gel conjugate viscosity couldbe selected to decrease with body temperature, so as to induce therelease of the drug once placed in the body. Alternatively, a saturatedsponge or patch placed just proximal to the filter could release thedrug.

[0055] While the drug could be released passively by infusion,dissolution or leaching, as described above, the need for providing adrug at certain intervals could also be addressed. This could beaccomplished by the use of barrier technologies, (i.e. a film over thedrug) to control the kinetics of the drug release. The thickness of thefilm could vary in regions of the device so the drug would be releasedin different amounts and/or at different places at various timeintervals.

[0056] Drug release may also be controlled by a change in environmentalconditions such as a pressure drop across the device, causing increaseddrug release as the device becomes occluded. Stimuli sensitive polymers(SSP's) are currently available as coatings that are capable ofresponding to their environment and controlling the delivery offunctional substances. The SSP fibers may be swollen with water so as toentrap an active substance. When there is an environmental change suchas temperature, pH, light, salt, electrical field or stress, thecollapse of the SSP acts as a self-activating mechanism for releasingthe drug. The environmental change may be a change in viscosity orpressure caused by platelet activation and aggregation followed bycoagulation leading to fibrin formation in the blood of the patient'svascular system. The SSP fibers could incorporate the drug eluting beads50 discussed above such as by entrapping the beads 50 in the SSP fibers.The beads 50 may then be released when there is a change in condition ofthe bloodstream viscosity or pressure indicating the onset of filter 12occlusion. Such a change in conditions would activate the drug deliverymechanism and release the beads 50 and drugs therein.

[0057] The formation of thrombus often occurs distal to the filter 12,in the areas of stagnant and/or disrupted blood flow patterns. Thus, thedrug delivery methods discussed herein may be positioned distal to thefilter 12 to address this problem. Additionally, flow re-directors couldbe placed distal to the filter 12 so as to encourage the drug to remainconcentrated around the filter 12. An example of such a flow re-directoris a variable size vascular plug placed distal to the filter 12 to beused as a regulator of flow and/or pressure across the filter 12. Suchcontrol of flow in combination with a drug delivery system may furtherfacilitate filter 12 patency.

[0058]FIG. 8 illustrates another embodiment of a drug delivery devicefor delivering a drug to a protection device 10 for maintaining filter12 patency. In this embodiment, an expandable bladder 82 is used toinfuse the drug from a reservoir or cavity 80, defined by a lumen 72through hostwire 14, through a plurality of delivery ports 74. Thebladder 82 is expanded within lumen 72 to force the drug positionedwithin the reservoir 80 to pass through a delivery portion where thedrug is released through weep holes or ports 74. Once the drug isdelivered through the ports 74 it is able to be locally delivered to thefilter 12 of the protection device 10 and the area surrounding thefilter 12.

[0059] As illustrated, the delivery ports 74 may be a plurality ofapertures 74 spaced about the side wall 76 of the reservoir 80. Theapertures 74 form channels from the interior of the lumen 72 to theexterior of the side wall 76 for allowing the drug to be delivered fromwithin the lumen 72 to the exterior of the tubular member 81. The drugdelivery mechanism 15 may deliver the drug by expanding within the lumen72 (for example, as a result of increased temperature) thereby forcingthe drug to exit the reservoir 80 and the delivery ports 74. As the drugis released from the lumen 72 it is able to be delivered to the filter12 portion of the protection device 10. The drug is then able tofacilitate continued patency of the filter 12.

[0060] As illustrated in FIG. 8, the drug delivery mechanism 15 may beactivated by the infusion of the drug delivery portion 80 with the drugfrom the expansion of an expandable bladder 82. The bladder 82 may be aninflatable member such as a balloon that is pre-inflated and affixed tothe interior of the tubular member The exit ports 74 allow for the drugto be channeled there-through to the outer surface of the wall of thedrug delivery structure. As the bladder 82 expands due to flow of drugthrough the apertures, the pressure within the bladder and within thehollow portion 80 decreases. The rate of expansion of the bladder 82 maybe controlled so as to control the rate at which the drug is deliveredfrom the device. For example, a bladder pre-inflated at low pressurewill result in a slower release of the drug than a bladder pre-inflatedat high pressure.

[0061] The tubular member 81 is a generally cylindrical tube having aside wall 76 with an inner lumen 72 extending therewithin. The tube 81has a plurality of apertures 74 formed through at the side wall 76 ofthe tubular member 81 allowing communication of a substance within theinner lumen 72 to the exterior of the side wall 76 The apertures 74 arespaced about the circumference of the side wall 76 and may have variousdiameters and be of a size and number to control the release rate of thedrug in cooperation with bladder pressure. The side wall 76 has anelongate dimension wherein the plurality of apertures 74 may be spacedalong at least a portion of the elongate dimension. The apertures 74 maybe staggered along the side wall circumference, such as in a spiralpattern, a ring pattern, or any other such combination random orordered, over the side wall 76. A portion of the side wall 76 may betapered outwardly.

[0062] Methods of delivering the drug include a pump powered byinduction, a screw-drive, an elastomer drive, or blood flow. Theelectromotive force or peristaltic action provided by the heart may alsobe used to drive the drug delivery mechanism 15. Alternatively, osmotic,hypertonic or capillary action could function as the driving force topump the drug through the tubular member. Any mechanism capable ofproviding a driving force to the drug may be employed such as the use oftemperature or ultrasound to initiate such driving force.

[0063] The tubular member 81 may allow the drug to be dispensed into thelumen 72 and/or maintained within the drug delivery portion of thedevice and delivered through the weep holes 74 in the wall 76 of thetubular member 81. The weep holes 74 are spaced within the wall 76 ofthe tubular member 81. A plurality of tubes may be incorporated having acorresponding plurality of sidewalls and each tubing having apredetermined number of apertures.

[0064]FIG. 9 illustrates a reservoir 80 that has a fluted portion 90 toincrease surface area on which coating capacity can be maximized. It iscontemplated that such a fluted lumen could be employed in theembodiment illustrated in FIG. 7. The fluted portion 90 can be coatedalong a length as at reference numeral 110 or a longer or shorterlength, as appropriate.

[0065] Turning now to FIGS. 10-11, it is contemplated that the drugdelivery mechanism illustrated in FIG. 8 may have more than a singlelumen 72. For example, FIG. 10 illustrates a first lumen 94 adjacent asecond lumen 96. Each lumen 94, 96 may be capable of delivering a drugtherefrom. It is contemplated that each lumen may be capable ofdelivering a different drug or that each lumen be capable of deliveringa component of a drug capable of mixing with the component in theadjacent lumen. It is further contemplated that any number of adjacentlumens may be incorporated into the drug delivery portion 80.

[0066]FIG. 11 illustrates a drug delivery mechanism 15 having a coaxiallumen 100 such that a first lumen 99 extends coaxially relative to awall 104 second coaxial lumen 100. Thus, each drug delivery lumen mayhave at least a single wall 76 with a plurality of weep holes 74,wherein the drug delivery mechanism may have a plurality of side walls76. The use of more than one lumen for simultaneous infusion of morethan one drug for in situ mixing can be employed to inhibit reactionsduring the intrinsic or common pathway of fibrin clot formation orplatelet activation and/or aggregation. The multiple lumens may beindividually, sequentially or simultaneously infused. The tubularmember, guide catheter (not shown) or an accessory catheter(not shown)could be charged with a reservoir of drugs.

[0067] The delivery ports 74 may be spaced in a variety of arrangementson the side wall 76 of the respective tubular members as illustrated inFIGS. 10-11.

[0068] Alternatively, if a plurality of side walls are present, thedelivery ports 74 may be spaced in alternative configurations on eachside wall 76. For example, the delivery ports 74 may be spacedcircumferentially at various along the length of the wall, the ports 74may be arbitrarily patterned along the length of the wall, the ports 74may be spaced so as to helically wind about the length of the wall, andany combination or other such means of spacing, random or ordered so asto provide a plurality of delivery ports 74 about the side wall of thelumen 72 for delivering of a drug from the lumen 72.

[0069] The spacing and sizing of the apertures 74 may be configured tocontrol the rate of diffusion of the drug into the blood vessel. Theapertures 74 may have a predetermined size and spacing that allows for aslower or faster relative rate of diffusion. Controlling the rate ofdiffusion may lessen the shear stresses on blood flowing toward thefilter 12. A lesser shear stress is preferable over a high pressure drugdelivery that may create an accelerated flow pattern that could bedetrimental to flow dynamics surrounding the filter 12.

[0070] After the drug is delivered through the delivery port 74 it isable to become infused within the fluid flowing on the outer surface ofthe tubular member 81. For example, if the tubular member 81 ispositioned within a blood stream the drug will become infused within theblood stream. As the blood stream is flowing toward the filter 12, thefilter 12 being downstream, the drug will likewise be delivered to thefilter 12 from a upstream location thus providing for local drugdelivery. Alternatively, the lumen 94 may be located adjacent to anotherlumen 96. The drug would then be delivered into the lumen 105 and beable to flow and intermix with the fluid, such as a drug or component,within the lumen 105. The combination of the drugs from the first andsecond lumens 94, 96 may then be delivered into a fluid external to thelumen 105, such as the blood within a blood vessel.

[0071] In another alternative, the first tubular member 102 may becoaxial with a second tubular member 104. Thus the drugs within thefirst and second tubes 102, 104 may be delivered into the bloodstreamdirectly without intermixing prior to passage through ports 74, so as tomix and be delivered externally to the filter 12. As the drug isdelivered into a fluid such as blood, it is able to be delivered withthe flow of fluid to distal portions of the protection device 10,preferably to the filter 12. The drug may provide for an increasedconcentration of anti-coagulants, or other such drugs preventingformation of thrombi and occlusions of the filter 12. The localconcentration of the drug may also cover portions of the drug deliverymechanism 15 and tubular members and portions of the protection device10 that are proximal and distal to the filter 12. Infusing the drugupstream from the filter 12 and allowing it to flow to the filter 12 mayalso deliver the drug to local stasis areas in the vicinity of thefilter 12 where it can minimize and/or prevent clotting and/orcoagulation. This may flush loose partially adherent emboli, that mayotherwise become dislodged during or after filter 12 removal, into thefilter 12 along with the drug delivery medium.

[0072] The shape, size, and workings of the filter 12 are not criticalto the efficacy of the present invention. The filter 12 used in theembodiments of the present invention is contemplated as a possible typeof filter 12 to be used with the present invention. However, the filter12 may assume a variety of configurations such as a basket, a windsock,a flat shape, and elongated shape, the filter 12 may have a cover or analternating periphery or diameter. The filter 12 must merely perform thefunction of preventing the passage of particulate material of apredetermined size. The present invention addresses the delivery of adrug to a filter 12 to facilitate filter patency, and contemplates thedrug delivery system disclosed herein as incorporating a variety offilter sizes, shapes and configurations. The filter 12 may be attachedto the distal portion of a hostwire 14. The hostwire 14 may extendthrough the lumen 72 containing the drug. Alternatively, the hostwire 14may have a hollow portion 80 for containing and delivering the drugtherefrom.

[0073] Possible drugs to be used in the present invention includeIIb/IIIa inhibitors and any other such anti-platelet agents, or drugsfor preventing occlusions to the filter 12 during a medical procedure,such as heparin, Aggrastat or Integrilin or fibrinolytic drugs. Thedrugs may be precursors or drug agents to be mixed with other fluids soas to effect the purpose of the present invention. For example, a drugin a first lumen 72 may not be capable of preventing occlusion unless oruntil mixed with a drug in the second lumen 72 or when mixed with blood,for example. Such drugs help to maintain filter 12 patency even withreduced filter 12 pore sizes without negative effects of systemic drugadministration such as excessive bleeding.

[0074] In summary, an advantage of the present invention is increasedpatency, such as the length of time patency is maintained within thefilter, or the degree of patency allowed as a result of drug delivery tothe protection device. This gives the operator or physician additionaltime to perform a medical procedure, thus making the procedure safer forthe patient.

[0075] It will be understood that this disclosure, in many respects, isonly illustrative. Changes may be made in details, particularly inmatters of shape, size, material, and arrangement of parts withoutexceeding the scope of the invention. Accordingly, the scope of theinvention is as defined in the language of the appended claims.

What is claimed is:
 1. A medical device for insertion into thevasculature of a patient, comprising: a distal member for allowingpassage of a fluid, and a self-activating drug delivery mechanismproximate said distal member for delivering a drug to said distal memberto induce continued patency to said distal member.
 2. The medical deviceof claim 1, wherein said self-activating drug delivery mechanismincludes a plurality of beads.
 3. The medical device of claim 2, whereinsaid self-activating drug delivery mechanism is activated by piercing ofsaid beads upon deployment of said medical device.
 4. The medical deviceof claim 2, wherein said self-activating drug delivery mechanism isactivated by dissolving a coating applied to said beads.
 5. The medicaldevice of claim 1, wherein said distal member is a filter.
 6. Themedical device of claim 5, wherein said filter is expandable about ahostwire.
 7. The medical device of claim 6, wherein said self-activatingdrug delivery mechanism is a plurality of beads.
 8. The medical deviceof claim 7, wherein said plurality of beads are carried by saidhostwire.
 9. The medical device of claim 8, wherein said plurality ofbeads are activated by releasing said beads from said hostwire andimpacting said beads against said filter.
 10. The medical device ofclaim 7, wherein said plurality of beads are positioned on said filter.11. The medical device of claim 1, wherein said self-activating drugdelivery mechanism is a micro-electro mechanical system (MEMS).
 12. Themedical device of claim 11, wherein said MEMS dispenses said drug atpredetermined intervals.
 13. The medical device of claim 11, whereinsaid MEMS is located on a hostwire extending proximate said distalmember of said medical device.
 14. The medical device of claim 13,wherein a second MEMS is located proximate said distal member of saidmedical device.
 15. The medical device of claim 1, wherein a hostwire onwhich said distal member is mounted passes through a lumen.
 16. Themedical device of claim 15, wherein said self-activating drug deliverymechanism is located within said lumen.
 17. The medical device of claim16, wherein said lumen houses an expandable bladder.
 18. The medicaldevice of claim 17, wherein said expandable bladder expands in responseto a change in environmental conditions.
 19. The medical deviceaccording to claim 1, wherein self-activating drug delivery mechanism isactivated by expansion of an expandable bladder.
 20. A vascular device,comprising: a hostwire having a distal portion, the hostwireinterposable in the vasculature of a patient; a filter expandableoutwardly from said distal portion of said hostwire, said filternormally allowing passage of fluid therethrough; and a drug eluting beadfor facilitating patency of said filter by releasing a drug upflow ofsaid filter.
 21. The vascular device according to claim 20, wherein saiddrug eluting bead releases said drug upon impact with said filter. 22.The vascular device according to claim 21, wherein said drug elutingbead impacts said filter upon expansion of said filter.
 23. The vasculardevice according to claim 20, wherein said drug eluting bead releasessaid drug by dissolving a coating encapsulating said bead.
 24. Thevascular device according to claim 23, wherein said coating is dissolvedby an activating agent in the blood of a patient.
 25. The vasculardevice according to claim 25, wherein said bead is porous.